Power amplifier torque responsive disconnect



H. TROEGER 3,465,859

POWER AMPLIFIER TORQUE RESPONSIVE DISCONNEC'I' Sept. 9, 1969 2 Sheets-Sheet 1 Original Filed June 14, 1966 HENRY TROEGER INVENTOR \N\\\ O on O? of 2 Or Pu wmok P 9, 1959 H. TROEGER 3365,859

POWER AMPLIFIER TORQUE RESPONSIVE DISCONNECT Original Filed June 14, 1966 2 Sheets-Sheet 2 AFT FORE

[Mg/l HENRY TROEGER INVENTOR.

3,465,859 POWER AMPLIFIER TORQUE RESPONSIVE DISCONNECT Henry Troeger, Cooperstown, N.Y., assignor to The Bendix Corporation, a corporation of Delaware Original application June 14, 1966, Ser. No. 557,434, now Patent No. 3,407,677, dated Oct. 29, 1968. Divided and this application Aug. 2, 1968, Ser. No. 749,728

Int. Cl. F16d 23/ 00, 7/02, 43/20 US. Cl. 19256 4 Claims ABSTRACT OF THE DISCLOSURE This invention is a division of my co-pending applicaton SN 557,434 filed June 14, 1966, now Patent No. 3,407,677, and entitled Power Amplifier.

The present invention relates to a mechanical power amplifier position control unit and, more particularly, to a power amplifier position control unit for controlling the movement of aircraft control surfaces or parameters such as ailerons, rudders, elevators, turbine engine exhaust nozzles and the like.

In mechanical power amplifiers of the type to which the present invention relates, it is necessary to provide overtorque protection to protect the drive mechanism from damage under overtorque conditions. To be practical, such protection must be capable of producing rapid disconnect, yet must be resettable in order to minimize cost and to avoid replacement delays once the source of the overtorque has been located and corrected. It is, therefore, an object of the present invention to provide an overtorque protective mechanism for a mechanical power amplifier having the above described beneficial characteristics.

It is a further object of the present invention to provide a power amplifiers postion control unit which has a novel resettable overload torque release mechanism which is simple and reliable.

In the drawings wherein a power amplifier position control system embodying the invention is illustrated:

FIGURE 1 is a schematic of the power amplifying position and control unit shown in a longitudinal view.

FIGURE 2 is a fragmentary longitudinal view of the power unit showing the output gearing and the overload release device.

Output and overload release system The output mechanism and the torque release safety mechanism are shown in detail in FIGURE 2. Rotatably journalled to the main drive shaft 40 is main drive gear 200 which engages output gears 202, normally rotatable with output shafts 204. Output gears 202 are disposed about main drive gear 200 and are driven at a reduced speed from and in the opposite direction of main drive gear 200. An overload mechanism is provided to disconnect the main drive shaft 40 from the load if an excessive torque load occurs on any output drive shaft. The output shafts have an adapter or drive end 206 formed therein to receive the mated end 208 of the torque United States Patent "ice sensing device 210. On the other end of the shafts 210 is a head 212 having a keyway for receiving key 214. The key 213 interconnects the output drive gear 202 to the torque measuring shafts 210, so that shafts 210 provide the torque transmitting connection between gears 202 and output shafts 204. Output shaft sleeves 220, which are rotatable with output gears 202, have splines 218 which are adapted to engage, but are normally mismatched, with splines 216 of the output shafts and shaft sleeves 22 0 are biased in the mismatched position by a latch or spring retainer 222 which is compressively confining a spring 224 between the output gears 202 and the output shaft sleeves 220. If excessive torque is developed along the torque measuring arm 210, the keyed head end of the arm 212 will rotate with respect to the adapter 208 and cause an output gear 202 to rotate relative to an output shaft 204. This rotation will cause the mismatched splines 216 and 218 to become aligned and the sleeve 220 will be propelled down the output shaft 204.

The main shaft 40 has a sleeve member 230 slidably journalled thereon for rotation therewith. Sleeve member 230 has dentil teeth or curvics 234 formed on one end thereof which mate with or engage similar torque transmitting teeth 236 formed on the transverse end of the main drive gear 200 to normally rotate drive gear 200 with drive shaft 40. A latch member 238 having a conical inner surface is resiliently biased by spring 232 to hold ball bearing members 240 in annular groove 239 formed in the output shaft 40 to keep the torque transmitting teeth 234 and 236 normally locked into engagement. When, however, due to excessive torque, an output shaft sleeve 220 is propelled aft, as referenced in the drawing, it will engage the main shaft latch member 238 and pull it aft as shown in the drawing. As the main latch member 238 is moved aft, the ball bearing members 240 are released and spring 232 is further compressed. The balls 240 are urged out of the groove 239 by centrifugal force, allowing the spring 232 to propel the main sleeve 230 aft," causing disengagement of the tooth surfaces 234 and 236, thereby disconnecting the output from the control device.

Reset of the device can be readily achieved by manually demeshing the splines 216 and 218 under a no-load condition so that torque sensing quill will provide the necessary shaft 204 rotation relative to the sleeve 220 to produce the required mismatched condition. The drive latch mechanism can then be reset by prying forward the main drive sleeve 230 until the ball bearing members 240 are locked into the groove 239 by the conical surface of the latch member 238 thereby locking the torque transmitting teeth 234 and 236 together.

Operation Turning now to FIGURE 1 wherein a schematic of the power amplifier position control unit is shown. In operation, the unit acts as follows: Assuming that the power amplifier is in a neutral position and that the output is in a position which is stable with respect to the input wherein the input control linkage 102 is moved in the open direction as indicated in the drawing, it will position the input-output summing lever 104 in the fore direction as indicated in the drawing. This movement of the summing lever 104 will be transmitted by the linking member 107 to the multiplying lever which, in turn, will multiply the force and then transmit it to the second summing lever 131 which, through the pivot connection will move the variable speed ball cage member 96 in the forward direction and cause the cam disc drive plate 92 to be driven faster in the counterclockwise direction. This, in turn, will cause the balls 76 to translate, causing the motion of the cam disc 70 and, in turn, the bell crank arm 60 which positions the brake members. Counterclockwises motion of the cam disc 70 will cause the bell crank arm 60 which positions the brake members. counterclockwise motion of the cam disc 70 will cause the bell crank arm to be moved in the upward direction, as referenced in the drawing and will cause the actuation of the pressure plate 44 to be moved in the forward direction, causing the engagement of the brake discs with the brake member 48 to prevent the rotation of the planet carrier 24 and releasing the first ring gear at holding brake member 36. In this condition, the input shaft 12 transmits power through the sun gear 16 to the planet gear member 22 which causes the rotation of the first ring gear 36 which, in turn, is engaged by the first planet carrier 34 with gears 35 formed thereon and causes the rotation of the planet carrier '32 which is mechanically linked through the arm 42 to the main output shaft 40. The rotation of the main shaft 40 is counterclockwise direction. Conversely, if the power amplifier position control unit has been in the neutral position to begin with and the linkage 102 has been moved in the closed direction, this would cause the levers 104 and 120 to be moved aft, causing the movement of the variable ball speed cage member 96 to be aft and decreasing the speed of the first cam disc drive 92. Decreasing the speed of the drive 92 would cause the balls 76 to rotate about the main shaft 14 in a clockwise direction and would pull the bell crank arm inward relative to the housing. This motion of the bell crank arm would move the pressure plate 46 aft as shown in the drawing and would prevent the rotation of the second ring gear member 38. In this mode of operation, the input gear 12 is rotating the sun gear 16 which causes the rotation of the planet gear 21 and the planet carrier 32 is rotated in a clockwise direction. The rotation of the planet carrier 32 is linked through the arm 42 to the main output shaft 40 which is rotated in a clockwise direction also. The first planet gear 22 has a first ring gear 36 which is free to rotate and transmit no torque. If, as in the embodiment shown, the number of teeth in the second ring gear member 38 equals the sum of the number of teeth on the sun gear 16 and the number of teeth on the first ring gear 36, then the gear reduction ratio in both directions is equal.

It can be seen that the device is a fully-automatic, selfcontained, power amplifying and position control unit in which even small differences between input and output are capable, by virtue of the integrating nature of the variable speed elements, of providing sufficient energy to operate the brakes to provide adequate torque to reposition the output and reduce the error to an acceptable value. The device can be made as sensitive to variations between the output position and input selector position as is desired. It can be seen that from the small inertia of the control system that response time is quite short and that positioning can be exceedingly precise. The device is self-protecting in that its overload release mechanism will prevent damage to the unit by providing rapid disconnect upon sensed overload. Further, the overload release can be readily and easily manually reset by any one of a number of known methods. The reference directions shown and described have been shown merely for the purposes of description and are not to be deemed limiting in any sense. The device is, of course, capable of operating at a wide range of physical environments. It may be air-cooled and does not need separate cooling. Furthermore, the device is non-inertial and will operate in a zero gravity environment.

It can be readily appreciated that by positioning the input lever that, in turn, the variable speed ball cage 92 is positioned to control the cam disc member which, in turn, controls the braking mechanisms to determine which direction, if any, the output shaft 40 will be driven. The feedback from output position is furnished by the output position threaded member 114 and is, in turn, fed around to the input position levers. Further, the control mechanism, the cam disc, has a feedback arm which is connected to the variable speed ball cage member.

I claim:

1. A release mechanism comprising:

drive means;

an input gear means operatively coupled to said drive means;

a shaft means having an adapter and a first spline;

a shaft sleeve having a second spline adapted to engage said first spline and normally held in a mismatched position relative to said first spline, said shaft sleeve rotatable with said gear means;

a torque sensing means having one end thereof held by said shaft adapter and the other end thereof connected to said gear means to rotate said shaft means with said gear means;

resilient means compressively confined between said gear means and said shaft sleeve;

said torque sensing means operative at a predetermined torque to permit relative rotation of said gear means with respect to said shaft to engage said normally mismatched first and second splines; and

said sleeve movable on said shaft when said first and second splines are engageably aligned to disconnect said gear means from said drive means.

2. The release mechanism as claimed in claim 1 wherein said drive means comprises:

a drive shaft having a drive sleeve slidable journalled thereon, said drive sleeve having a first torque transmitting surface on one transverse end thereof;

a drive gear having a second torque transmitting surface on one transverse end thereof adapted to engage said drive sleeve first torque transmitting surface;

decoupling means for disconnecting said drive gear and drive sleeve torque transmitting surfaces in response to axial movement of said shaft sleeve.

3. The release mechanism as claimed in claim 2 wherein:

said decoupling means comprises ball bearing means received in said drive sleeve means; and including:

a resiliently-biased drive sleeve latch means biasing said ball bearing means to normally cause engagement of said drive gear and drive sleeve torque transmitting surfaces.

4. The release mechanism as claimed in claim '3 including further:

shaft sleeve latch means movable with said shaft sleeve, operative to engage said drive sleeve latch means to disconnect said gear and drive sleeve torque transmitting surfaces in response to said torque sensing means position.

References Cited UNITED STATES PATENTS 3,269,498 8/1966 Hoenig et al. 192-56 AL L. SMITH, Primary Examiner A. D. HERRMANN, Assistant Examiner U.S. Cl. X.R. 6428 

